Device for the shaping of glass tubes

ABSTRACT

In order to shape the necks of glass tubes (1) on glass processing machines, use is made of a device with two shaping tools, one of which takes the form of a ring (3) surrounding the glass tube (1) and the other shaping tool consisting of a roller (2).

The invention relates to a device for the shaping of glass tubes, withtwo shaping tools which can be set in rotational movement and which canbe pressed in opposite directions against the circumference of thesoftened glass tube, in order to produce a contraction of the glasstube, said contraction corresponding to their profile.

In glass processing machines for producing small bottles from glasstubes, devices of the above type are used for shaping the necks of thebottles. In a relevant device known from DE 17 96 100 B2, shapingrollers arranged in pairs are held by jib arms which are movable to andfro in opposite directions and which, during the shaping process, aremoved towards the longitudinal axis of the glass tube in such a way thatthe latter is gripped in a pincer-like manner by the shaping rollers.During shaping, essentially linear contact occurs between the shapingrollers and the glass tube softened by the effect of heat. As experiencehas shown, irregularities in a glass tube, particularly fluctuations inits wall thickness, may result in the actual shape of the bottle neckdeviating from the desired shape to a greater extent than ispermissible.

The object on which the invention is based is to afford a possibilityfor improving the shaping accuracy of relevant devices. The set objectis achieved, according to the invention, in that, in a device of thistype, one of the two shaping tools is designed as a ring which surroundsthe glass tube and the other shaping tool formed by a roller.

The device according to the invention offers the advantage that itreacts to deviations in the desired dimensions of glass tubes lesssensitively than known devices. The reasons for the improved mode ofoperation would seem to be the contact region between the outer shapingtool designed as a ring and the softened glass tube, said contact regionbeing enlarged in relation to linear contact, and the reduction in anglein the region of the wedge-shaped gap between the inner face of theouter shaping tools and the outer face of the glass tube.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and features of the invention emerge from the subclaimsand from the following description of the accompanying drawing. In this:

FIG. 1 shows a diagrammatic side view of a device, partially in section,and

FIG. 2 shows a top view of the device according to FIG. 1, likewisepartially in section.

In the figures, 1 denotes a glass tube, from which small glass bottlesare produced on a known glass processing machine. The figures show theposition of the shaping tools, used for producing the neck of the glasstube 1, at the end of the shaping operation. The shaping tools areformed by a roller 2 and a ring 3 surrounding the roller 2. A rotationalmovement illustrated by reference numeral 5 is imparted to the roller 2by an electric motor (not shown) via a shaft 4, whilst three driverollers 8, 9 and 10 rotating in the same direction in the direction ofthe arrows 7 serve for driving the ring 3 in the direction of the arrow6, said drive rollers holding the ring 3 and being driven jointly by afurther electric motor (not shown), the rotational speed of the motorsused for driving the roller 2 and the ring 3 being controlled in such away that a rolling movement occurs between the shaping tools and theglass tube 1.

The shaft 4 of the roller 2 is mounted in a slide 12 movable to and froin the direction of the double arrow 11, whilst the shafts 13, 14 and 15of the drive rollers 8, 9, 10 and of the ring 3 held by these are eachmounted in a slide 17 so as to move in the direction of the double arrow16 in opposition to the movements of the slide 12. The two slides 12 and17 can additionally be moved up and down in the direction of the doublearrow 19 by means of a lifting slide 18. The slides 12, 17 and 18 aredriven by means known per se, the illustration and description of whichcan consequently be dispensed with.

During the shaping operation, a mandrel 20 penetrates into the loweropen end of the glass tube 1, as is likewise generally conventional andknown.

I claim:
 1. A device for the shaping of glass tubes, with two shapingtools which can be set in rotational movement and which can be pressedin opposite directions against the circumference of a softened glasstube, in order to produce a contraction of the glass tube, saidcontraction corresponding to their profile, wherein one of the twoshaping tools is designed as a ring which surrounds the glass tube andthe other shaping tool formed by a roller.
 2. The device as claimed inclaim 1, wherein the shaping tool formed by a ring is held by at leastthree drive rollers distributed over the ring circumference.
 3. Thedevice as claimed in claim 1, wherein shafts of drive rollers for theshaping tool designed as a ring are mounted in a slide which can executeto-and-fro movements directed perpendicularly to the longitudinal axisof the glass tube.
 4. The device as claimed in claim 1, wherein a shaftof the shaping tool designed as a roller is mounted in a slide which canexecute to-and-fro movements directed perpendicularly to thelongitudinal axis of the glass tube.
 5. The device as claimed in claim3, further comprising at least a pair of slides, said pair of slidesbeing movable in opposite directions.
 6. The device as claimed in claim1, wherein the shaping tools can be moved up and down by means of alifting slide.
 7. The device as claimed in claim 1, wherein a mandrelcan be introduced into the orifice of the glass tube.
 8. The device asclaimed in claim 2, wherein shafts of the drive rollers for the shapingtool designed as a ring are mounted in a slide which can executeto-and-fro movements directed perpendicularly to the longitudinal axisof the glass tube.
 9. The device as claimed in claim 4, furthercomprising at least a pair of slides, said pair of slides being movablein opposite directions.